[vsnet-grb-info 13842] GRB 130831A: THO optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15156
SUBJECT: GRB 130831A: THO optical observation
DATE:    13/09/01 06:48:23 GMT
FROM:    Veli-Pekka Hentunen at Taurus Hill Obs,A95  <veli-pekka.hentunen at kassiopeia.net>

Veli-Pekka Hentunen, Markku Nissinen, Harri Vilokki and Tuomo Salmi 
(Taurus Hill Observatory, Varkaus, Finland) report:

We have detected GRB 130831A optical afterglow at Taurus Hill Observatory
A95 (Varkaus, Finland). We used 0.35m C-14 OTA telescope (f =3910 mm),
NextGen 0.5X, Paramount ME and SBIG ST-8XME CCD camera. 
The observation was started 6.65 hours after the Swift trigger. Six unfiltered
images with 600 sec exposure time were made.

The afterglow was detected at following position RA 23 54 29.7 and
DEC +29 25 46.6.

The following magnitude was obtained from the observation using NOMAD1
1194-0619856 (R=16.240) as the comparison:

Tmid(h)+T0    Filter              Exp. time          Mag                Mag err. 
7.218              unfiltered        6x600              18.01CR         0.08

A png preview of the observation showing the position of the afterglow is 
available at this URL: 
www.kassiopeia.net/wp-content/uploads/2013/09/GR130831A_comparison.png